Antenna structure

ABSTRACT

An antenna structure includes a housing, a first feed source, and a second feed source. The first feed source is electrically coupled to a first radiating portion of the housing and adapted to provide an electric current to the first radiating portion. The second feed source is electrically coupled to one of a second radiating portion or a third radiating portion of the housing. The other one of the second radiating portion or the third radiating portion is electrically coupled to the first radiating portion.

FIELD

The subject matter herein generally relates to antenna structures, andmore particularly to an antenna structure of a wireless communicationdevice.

BACKGROUND

As electronic devices become smaller, an antenna structure for operatingin different communication bands is required to be smaller.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the present disclosure will now be described, by wayof embodiments only, with reference to the attached figures.

FIG. 1 is a partial isometric view of an embodiment of an antennastructure in a wireless communication device.

FIG. 2 is an isometric view of the communication device in FIG. 1.

FIG. 3 is a diagram of the antenna structure in FIG. 1.

FIG. 4 is a diagram of current paths of the antenna structure in FIG. 3.

FIG. 5 is a block diagram of a switching circuit.

FIG. 6 is a graph of S11 values of an LTE-A low-frequency mode.

FIG. 7 is a graph of total radiation efficiency of the LTE-Alow-frequency mode.

FIG. 8 is a graph of S11 values of an LTE-A mid-frequency mode.

FIG. 9 is a graph of total radiation efficiency of the LTE-Amid-frequency mode.

FIG. 10 is a graph of S11 values of an LTE-A high-frequency mode.

FIG. 11 is a graph of total radiation efficiency of the LTE-Ahigh-frequency mode.

FIG. 12 is a diagram of a second embodiment of an antenna structure.

FIG. 13 is a diagram of current paths of the antenna structure in FIG.12.

FIG. 14 is a graph of S11 values of the LTE-A low-frequency mode.

FIG. 15 is a graph of total radiation efficiency of the LTE-Alow-frequency mode.

FIG. 16 is a graph of S11 values of a LTE-A mid-frequency mode.

FIG. 17 is a graph of total radiation efficiency of the LTE-Amid-frequency mode.

FIG. 18 is a graph of S11 values of a LTE-A high-frequency mode.

FIG. 19 is a graph of total radiation efficiency of the LTE-Ahigh-frequency mode.

FIG. 20 is a diagram of a third embodiment of an antenna structure.

FIG. 21 is a diagram of current paths of the antenna structure in FIG.20.

FIG. 22 is a graph of S11 values of a LTE-A low-frequency mode.

FIG. 23 is a graph of total radiation efficiency of LTE-A mid andhigh-frequency modes.

FIG. 24 is a graph of total radiation efficiency of the LTE-Alow-frequency mode of a first antenna of the antenna structure.

DETAILED DESCRIPTION

It will be appreciated that for simplicity and clarity of illustration,where appropriate, reference numerals have been repeated among thedifferent figures to indicate corresponding or analogous elements.Additionally, numerous specific details are set forth in order toprovide a thorough understanding of the embodiments described herein.However, it will be understood by those of ordinary skill in the artthat the embodiments described herein can be practiced without thesespecific details. In other instances, methods, procedures and componentshave not been described in detail so as not to obscure the relatedrelevant feature being described. The drawings are not necessarily toscale and the proportions of certain parts may be exaggerated to betterillustrate details and features. The description is not to be consideredas limiting the scope of the embodiments described herein.

Several definitions that apply throughout this disclosure will now bepresented.

The term “coupled” is defined as connected, whether directly orindirectly through intervening components, and is not necessarilylimited to physical connections. The connection can be such that theobjects are permanently connected or releasably connected. The term“comprising” means “including, but not necessarily limited to”; itspecifically indicates open-ended inclusion or membership in aso-described combination, group, series and the like.

FIG. 1 and FIG. 2 show an embodiment of an antenna structure 100applicable in a mobile phone, a personal digital assistant, or otherwireless communication device 200 for sending and receiving wirelesssignals.

As shown in FIG. 3, the antenna structure 100 includes a housing 11, afirst feed source 12, a first matching circuit 13, a second feed source14, and a second matching circuit 15.

The housing 11 includes at least a middle frame 111, a border frame 112,and a backplane 113. The middle frame 111 is substantially rectangular.The middle frame 111 is made of metal. The border frame 112 issubstantially hollow rectangular and is made of metal. In oneembodiment, the border frame 112 is mounted around a periphery of themiddle frame 111 and is integrally formed with the middle frame 111. Theborder frame 112 receives a display 201 mounted opposite the middleframe 111. The middle frame 111 is a metal plate mounted between thedisplay 201 and the backplane 113. The middle frame 111 supports thedisplay 201, provides electromagnetic shielding, and enhances durabilityof the wireless communication device 200.

The backplane 113 is made of insulating material, such as glass. Thebackplane 113 is mounted around a periphery of the border frame 112 andis substantially parallel to the display 201 and the middle frame 111.In one embodiment, the backplane 113, the border frame 112, and themiddle frame 111 cooperatively define an accommodating space 114. Theaccommodating space 114 receives components (not shown) of the wirelesscommunication device 200.

The border frame 112 includes at least an end portion 115, a first sideportion 116, and a second side portion 117. In one embodiment, the endportion 115 is a bottom end of the wireless communication device 200.The first side portion 116 and the second side portion 117 face to eachother and are substantially perpendicular to the end portion 115.

In one embodiment, the border frame 112 includes a slot 120, a first gap121, and a second gap 122. The slot 120 is substantially U-shaped and isdefined in an inner side of the end portion 115. In one embodiment, theslot 120 extends along the end portion 115 and extends toward the firstside portion 116 and the second side portion 117. The slot 120 insulatesthe end portion 115 from the middle frame 111.

In one embodiment, the first gap 121 and the second gap 122 are locatedon the end portion 115 and are spaced apart. The first gap 121 and thesecond gap 122 cut across and cut through the border frame 112. Thefirst gap 121 and the second gap 122 are connected to the slot 120. Theslot 120, the first gap 121, and the second gap 122 separate the housing11 into a first radiating portion A1, a second radiating portion A2, anda third radiating portion A3. In one embodiment, the first radiatingportion A1 is located between the first gap 121 and the second gap 122,the second radiating portion A2 is a portion of the border frame 112located between the first gap 121 and an endpoint E1 of the first sideportion 116, and the third radiating portion A3 is a portion of theborder frame 112 located between the second gap 122 and an endpoint E2of the second side portion 117. In one embodiment, the first radiatingportion A1 is insulated from the middle frame 111. An end of the secondradiating portion A2 adjacent the endpoint E1 and an end of the thirdradiating portion A3 adjacent the endpoint E2 are coupled to the middleframe 111.

In one embodiment, the border frame 112 has a thickness D1. The slot 120has a width D2. The first gap 121 and the second gap 122 have a widthD3. D1 is greater than or equal to 2*D3. D2 is less than or equal tohalf of D3. In one embodiment, the thickness D1 of the border frame 112is 2-6 mm, the width D2 of the slot 120 is 0.5-1.5 mm. The width D3 ofthe first gap 121 and the second gap 122 is 1-3 mm.

In one embodiment, the slot 120, the first gap 121, and the second gap122 are made of insulating material, such as plastic, rubber, glass,wood, ceramic, or the like.

The wireless communication device 200 further includes at least oneelectronic component, such as a first electronic component 21, a secondelectronic component 23, and a third electronic component 25. The firstelectronic component 21 may be a universal serial bus (USB) port locatedwithin the accommodating space 114. The first electronic component 21 isinsulated from the first radiating portion A1 by the slot 120. Thesecond electronic component 23 may be a speaker and is mountedcorresponding to the first gap 121 and is spaced 4-10 mm from the slot120. The third electronic component 25 may be a microphone and ismounted within the accommodating space 114. The third electroniccomponent 25 is located between the second electronic component 23 andthe slot 120 and is adjacent the second gap 122. In one embodiment, thethird electronic component 25 is insulated from the first radiatingportion A1 by the slot 120.

In another embodiment, the second electronic component 23 and the thirdelectronic component 25 can be mounted in different locations accordingto requirements.

In one embodiment, the border frame 112 defines a port 123 in the endportion 115. The port 123 corresponds to the first electronic component21 so that the first electronic component 21 partially protrudes throughthe port 123. Thus, a USB device can be inserted in the port 123 toelectrically coupled to the first electronic component 21.

In one embodiment, the first feed source 12 and the first matchingcircuit 13 are received within the accommodating space 114. One end ofthe first feed source 12 is electrically coupled to a side of the firstradiating portion A1 adjacent the second gap 122 through the firstmatching circuit 13 for feeding a current signal to the first radiatingportion A1. The first matching circuit 13 provides a matching impedancebetween the first feed source 12 and the first radiating portion A1.

In one embodiment, the first feed source 12 divides the first radiatingportion A1 into a first radiating section A11 and a second radiatingsection A12. A portion of the border frame 112 between the first feedsource 12 and the first gap 121 is the first radiating section A11. Aportion of the border frame 112 between the first feed source 12 and thesecond gap 122 is the second radiating section A12. In one embodiment,the first feed source 12 is not positioned in the middle of the firstradiating portion A1. Thus, a length of the first radiating section A11may be greater than a length of the second radiating section A12.

In one embodiment, the second feed source 14 and the second matchingcircuit 15 are received within the accommodating space 114. One end ofthe second feed source 14 is electrically coupled to a side of thesecond radiating portion A2 adjacent the first gap 121 through thesecond matching circuit 15 for feeding a current signal to the secondradiating portion A2. The second matching circuit 15 provides a matchingimpedance between the second feed source 14 and the second radiatingportion A2.

As shown in FIG. 4, when the first feed source 12 supplies an electriccurrent, the electric current from the first feed source 12 flowsthrough the first matching circuit 13 and the first radiating sectionA11 toward the first gap 121 in sequence along a current path P1. Thus,the first antenna section A11 forms a monopole antenna to excite a firstresonant mode and generate a radiation signal in a first frequency band.

The electric current from the first feed source 12 can also flow throughthe first matching circuit 13, the second radiating section A12, andthen coupled to the third radiating portion A3 through the second gap122 along a current path P2. Thus, the first feed source 12, the secondradiating section A12, and the third radiating portion A3 form a coupledfeed antenna to excite a second resonant mode and generate a radiationsignal in a second frequency band.

When the second feed source 14 supplies electric current, the electriccurrent from the second feed source 14 flows through the second matchingcircuit 15 and the second radiating portion A2 along a current path P3.Thus, the second radiating portion A2 forms a loop antenna to excite athird resonant mode and generate a radiation signal in a third frequencyband.

In one embodiment, the first resonant mode is a Long Term EvolutionAdvanced (LTE-A) low-frequency mode, the second resonant mode is anLTE-A mid-frequency mode, and the third resonant mode is an LTE-Ahigh-frequency mode. The first frequency band is 700-960 MHz. The secondfrequency band is 1710-2170 MHz. The third frequency band is 2300-2690MHz.

In one embodiment, electric current from the first feed source 12 flowsto the first radiating section A11 to excite the LTE-A low-frequencymode, and the electric current from the first feed source 12 flowsthrough the second radiating section A12 to couple to the thirdradiating portion A3 to excite the LTE-A mid-frequency mode. Thus, thefirst radiating portion A1 and the third radiating portion A3 receiveelectric current from the first feed source 12 to excite the LTE-A lowand mid-frequency modes which include the frequencies 700-960 MHz and1710-2170 MHz.

In one embodiment, a portion of the slot 120 from the endpoint E1 andparallel to the first side portion 116 defines the length L1 of 1-10 mm.A portion of the slot 120 from the endpoint E2 and parallel to thesecond side portion 117 defines the length L2 of 1-10 mm. The lengths L1and L2 of the slot 120 are able to adjust the LTE-A middle andhigh-frequency modes.

As shown in FIG. 3, the antenna structure 100 further includes aswitching circuit 17. The switching circuit 17 is mounted within theaccommodating space 114 between the first electronic component 21 andthe third electronic component 25 adjacent to the third electroniccomponent 25. One end of the switching circuit 17 crosses over the slot120 and is electrically coupled to a side of the first radiating sectionA11 adjacent the first gap 121. Another end of the switching circuit 17is coupled to ground.

As shown in FIG. 5, the switching circuit 17 includes a switching unit171 and at least one switching component 173. The switching unit 171 iselectrically coupled to the first radiating section A11. The switchingcomponent 173 may be an inductor, a capacitor, or a combination of thetwo. The switching components 173 are coupled in parallel. One end ofeach of the at least one switching component 173 is electrically coupledto the switching unit 171, and the other end is coupled to ground. Thus,the first radiating section A11 is switched to electrically coupled todifferent ones of the switching components 173. Since each of theswitching components 173 has a different impedance, the switchingcomponents 173 are switched to adjust the LTE-A low-frequency mode.

In one embodiment, the switching circuit 17 includes four differentswitching components 173. The four different switching components 173are switched to be coupled to the first radiating section A11 to achievedifferent LTE-A low-frequency modes, such as LTE-A Band17 (704-746 MHz),LTE-A Band13 (746-787 MHz), LTE-A Band 20 (791-862 MHz), and LTE-A Band8(880-960 MHz).

The antenna structure 100 further includes at least one extendingportion 18. In one embodiment, the antenna structure 100 includes twoextending portions 18. The extending portions 18 are made of metal. Oneof the two extending portions 18 is connected to an end of the secondradiating section A12 adjacent to the second gap 122. A second one ofthe two extending portions 18 is connected to an end of third radiatingportion A3 adjacent to the second gap 122. The two extending portions 18face to each other.

A length and width of the extending portions 18 can be adjustedaccording to requirements to adjust an impedance value of the firstradiating portion A1, the second radiating portion A2, and the thirdradiating portion A3. The extending portions 18 can replace a groundcapacitor of the prior art.

FIG. 6 shows a graph of scattering values (S11 values) of the LTE-Alow-frequency mode. A plotline S61 represents S11 values of LTE-A Band17(704-746 MHz). A plotline S62 represents S11 values of LTE-A Band13(746-787 MHz). A plotline S63 represents S11 values of LTE-A Band17(791-862 MHz). A plotline S64 represents S11 values of LTE-A Band17(880-960 MHz).

FIG. 7 shows a graph of total radiation efficiency of the LTE-Alow-frequency mode. A plotline S71 represents LTE-A Band17 (704-746MHz). A plotline S72 represents LTE-A Band13 (746-787 MHz). A plotlineS73 represents LTE-A Band20 (791-862 MHz). A plotline S74 representsLTE-A Band8 (880-960 MHz).

FIG. 8 shows a graph of S11 values of the LTE-A mid-frequency mode.

FIG. 9 shows a graph of total radiation efficiency of the LTE-Amid-frequency mode.

FIG. 10 shows a graph of S11 values of the LTE-A high-frequency mode.

FIG. 11 shows a graph of total radiation efficiency of the LTE-Ahigh-frequency mode.

As shown in FIGS. 8-11, when the antenna structure 100 operates in theLTE-A Band17 (704-746 MHz), LTE-A Band13 (746-787 MHz), LTE-A Band20(791-862 MHz), and the LTE-A Band8 (880-960 MHz), the LTE-A mid andhigh-frequency mode range is from 1710-2690 MHz). The switching circuit17 only adjust the low-frequency mode and does not affect the mid andhigh-frequency modes.

FIG. 12 shows a second embodiment of an antenna structure 100 a for usein a wireless communication device 200 a.

The antenna structure 100 a includes a middle frame 111, a border frame112, a first feed source 12, a first matching circuit 13, a second feedsource 14 a, a second matching circuit 15 a, a switching circuit 17, andat least one extending portion 18 a. The wireless communication device200 a includes a first electronic component 21, a second electroniccomponent 23, and a third electronic component 25. The border frame 112includes a slot 120, a first gap 121, and a second gap 122. The firstgap 121 and the second gap 122 cut across and cut through the borderframe 112. The slot 120, the first gap 121, and the second gap 122separate the housing 11 into a first radiating portion A1, a secondradiating portion A2, and a third radiating portion A3.

The first electronic component 21 may be a USB port located within theaccommodating space 114. The first electronic component 21 is insulatedfrom the first radiating portion A1 by the slot 120. The secondelectronic component 23 may be a speaker and is mounted corresponding tothe first gap 121 and is spaced 4-10 mm from the slot 120. The thirdelectronic component 25 may be a microphone and is mounted within theaccommodating space 114. The third electronic component 25 is locatedbetween the second electronic component 23 and the slot 120 and isadjacent the second gap 122. In one embodiment, the third electroniccomponent 25 is insulated from the first radiating portion A1 by theslot 120.

One end of the first feed source 12 is electrically coupled to a side ofthe first radiating portion A1 adjacent the second gap 122 through thefirst matching circuit 13 for feeding a current signal to the firstradiating portion A1. The first matching circuit 13 provides a matchingimpedance between the first feed source 12 and the first radiatingportion A1.

One end of the switching circuit 17 is electrically coupled to a side ofthe first radiating portion A1 adjacent the first gap 121. Another endof the switching circuit 17 is coupled to ground.

A difference between the antenna structure 100 a and the antennastructure 100 is that in the antenna structure 100 a, a location of asecond feed source 14 a and a second matching circuit 15 a is different.Specifically, as shown in FIG. 13, when the first feed source 12supplies the electric current, the electric current from the first feedsource 12 flows through the first matching circuit 13 and the firstradiating portion A1, and then flows toward the first gap 121 and flowsthrough the switching circuit 17 to ground along a circuit path P1 a.Thus, the first radiating portion A1 forms a monopole antenna to excitea first resonant mode and generate a radiation signal in a firstfrequency band.

Electric current from the first feed source 12 can also flow along acurrent path P2 a through the first matching circuit 13 and the firstradiating portion A1, and then couple to the second radiating portion A2through the first gap 121. Thus, the first feed source 12, the firstradiating portion A1, and the second radiating portion A2 form a coupledfeed antenna to excite a second resonant mode and generate a radiationsignal in a second frequency band.

When the second feed source 14 a supplies electric current, electriccurrent from the second feed source 14 a flows through the secondmatching circuit 15 a and the third radiating portion A3 along a currentpath P3 a. Thus, the third radiating portion A3 forms a loop antenna toexcite a third resonant mode and generate a radiation signal in a thirdfrequency band.

In one embodiment, the first resonant mode is a Long Term EvolutionAdvanced (LTE-A) low-frequency mode, the second resonant mode is anLTE-A mid-frequency mode, and the third resonant mode is an LTE-Ahigh-frequency mode. The first frequency band is 700-960 MHz. The secondfrequency band is 1710-2170 MHz. The third frequency band is 2300-2690MHz.

Another difference between the antenna structure 100 a and the antennastructure 100 is that a location of extending portions 18 a isdifferent. The antenna structure 100 a includes two extending portions18 a made of metal. One of the extending portions 18 a is mounted to thefirst radiating portion A1 adjacent an end of the first gap 121, and theother one of the extending portions 18 a is mounted to the secondradiating portion A2 adjacent the other end of the first gap 121.

A length and width of the extending portions 18 a can be adjustedaccording to requirements thereby adjusting an impedance value of thefirst radiating portion A1, the second radiating portion A2, and thethird radiating portion A3. The extending portions 18 a can replace aground capacitor of the prior art.

FIG. 14 shows a graph of scattering values (S11 values) of the LTE-Alow-frequency mode. A plotline S141 represents S11 values of LTE-ABand17 (704-746 MHz). A plotline S142 represents S11 values of LTE-ABand13 (746-787 MHz). A plotline S143 represents S11 values of LTE-ABand20 (791-862 MHz). A plotline S144 represents S11 values of LTE-ABand8 (880-960 MHz).

FIG. 15 shows a graph of total radiation efficiency of the LTE-Alow-frequency mode. A plotline S151 represents LTE-A Band17 (704-746MHz). A plotline S152 represents LTE-A Band13 (746-787 MHz). A plotlineS153 represents LTE-A Band20 (791-862 MHz). A plotline S154 representsLTE-A Band8 (880-960 MHz).

FIG. 16 shows a graph of S11 values of the LTE-A mid-frequency mode.

FIG. 17 shows a graph of total radiation efficiency of the LTE-Amid-frequency mode.

FIG. 18 shows a graph of S11 values of the LTE-A high-frequency mode.

FIG. 19 shows a graph of total radiation efficiency of the LTE-Ahigh-frequency mode.

As shown in FIGS. 14 and 15, the low-frequency mode is excited by thefirst radiating portion A1, and the switching circuit 17 adjusts thelow-frequency mode to include the LTE-A Band17, the LTE-A Band13, theLTE-A Band20, and the LTE-A Band8. As shown in FIGS. 16 and 17, themid-frequency mode is excited by the second radiating portion A2 andincludes LTE-A 1710-2170 MHz. As shown in FIGS. 18 and 19, thehigh-frequency mode is excited by the third radiating portion A3 andincludes LTE-A 2300-2690 MHz.

The switching circuit 17 only adjusts the low-frequency mode to operatewithin LTE-A Band17, LTE-A Band13, LTE-A Band20, or LTE-A Band8. Theswitching circuit 17 does not affect operation of the mid andhigh-frequency modes.

FIG. 20 shows a third embodiment of an antenna structure 100 b.

The antenna structure 100 b includes a middle frame 111, a border frame112, a first feed source 12, a first matching circuit 13, a second feedsource 14 a, a second matching circuit 15 a, a switching circuit 17, andat least one extending portion 18 a. The wireless communication device200 a includes a first electronic component 21, a second electroniccomponent 23, and a third electronic component 25.

The border frame 112 includes a slot 120, a first gap 121, and a secondgap 122. The first gap 121 and the second gap 122 cut across and cutthrough the border frame 112. The slot 120, the first gap 121, and thesecond gap 122 separate the housing 11 into a first radiating portionA1, a second radiating portion A2, and a third radiating portion A3.

The first electronic component 21 may be a USB port located within theaccommodating space 114. The first electronic component 21 is insulatedfrom the first radiating portion A1 by the slot 120. The secondelectronic component 23 may be a speaker and is mounted corresponding tothe first gap 121 and is spaced 4-10 mm from the slot 120. The thirdelectronic component 25 may be a microphone and is mounted within theaccommodating space 114. The third electronic component 25 is locatedbetween the second electronic component 23 and the slot 120 and isadjacent the second gap 122. In one embodiment, the third electroniccomponent 25 is insulated from the first radiating portion A1 by theslot 120.

One end of the first feed source 12 is electrically coupled to a side ofthe first radiating portion A1 adjacent the second gap 122 through thefirst matching circuit 13 for feeding a current signal to the firstradiating portion A1. The first matching circuit 13 provides a matchingimpedance between the first feed source 12 and the first radiatingportion A1.

In one embodiment, the first feed source 12 divides the first radiatingportion A1 into a first radiating section A11 and a second radiatingsection A12. A portion of the border frame 112 between the first feedsource 12 and the first gap 121 forms the first radiating section A11,and a portion of the border frame 112 between the first feed source 12and the second gap 122 forms the second radiating section A12. In oneembodiment, the first feed source 12 is not positioned in the middle ofthe first radiating portion A1. Thus, a length of the first radiatingsection A11 may be greater than a length of the second radiating sectionA12.

One end of the switching circuit 17 is electrically coupled to a side ofthe first radiating section A11 adjacent the first gap 121. Another endof the switching circuit 17 is coupled to ground.

A difference between the antenna structure 100 b and the antennastructure 100 is that in the antenna structure 100 b, locations of asecond feed source 14 b and a second matching circuit 15 b aredifferent. Specifically, the second feed source 14 b is not adjacent tothe first gap 121 and is not electrically coupled to the secondradiating portion A2. In one embodiment, one end of the second feedsource 14 b is electrically coupled to a side of the third radiatingportion A3 adjacent to the second gap 122 through the second matchingcircuit 15 b to feed a current signal to the third radiating portion A3.The second matching circuit 15 b provides a matching impedance betweenthe second feed source 14 b and the third radiating portion A3.

In one embodiment, the extending portion 18 are omitted from the antennastructure 100 b.

As shown in FIG. 21, when the first feed source 12 supplies electriccurrent, the electric current from the first feed source 12 flowsthrough the first matching circuit 13 and the first radiating sectionA11, and then flows toward the first gap 121 and flows through theswitching circuit 17 to ground along a circuit path P1 b. Thus, thefirst radiating section A11 forms a monopole antenna to excite a firstresonant mode and generate a radiation signal in a first frequency band.

Electric current from the first feed source 12 can also flow along acurrent path P2 b through the first matching circuit 13 and the secondradiating section A12, and then to the second gap 122 to excite a secondresonant mode and generate a radiation signal in a second frequencyband. In addition, electric current from the first feed source 12 flowsthrough the first matching circuit 13 and the first radiating sectionA11, and then flows to the second radiating portion A2 through the firstgap 121 along a path P3 b to excite a third resonant mode and generate aradiation signal in a third frequency band.

When the second feed source 14 b supplies electric current, the electriccurrent from the second feed source 14 b flows through the secondmatching circuit 15 b and the third radiating portion A3 along a currentpath P4 b. Thus, the third radiating portion A3 forms a loop antenna toexcite a fourth resonant mode and generate a radiation signal in afourth frequency band.

In one embodiment, the first resonant mode is a Long Term EvolutionAdvanced (LTE-A) low-frequency mode, the second resonant mode is anLTE-A mid-frequency mode, the third resonant mode is an LTE-Ahigh-frequency mode, and the fourth resonant mode is an LTE-Amid-high-frequency mode. The first frequency band is 700-960 MHz. Thesecond frequency band is 1710-2170 MHz. The third frequency band is2300-2690 MHz. The fourth frequency band is 1710-2170 MHz and 2300-2690MHz.

The antenna structure 100 b forms a multiple-input multiple-output(MIMO) antenna structure to excite two groups of LTE-A mid andhigh-frequency modes. Electric current from the first feed source 12flows to the first radiating portion A1 and is coupled to the secondradiating portion A2 to excite a first group of LTE-A low, mid, andhigh-frequency modes. In addition, electric current from the second feedsource 14 b flows to the third radiating portion A3 to excite a secondgroup of LTE-A mid and high-frequency modes. Thus, the first feed source12, the first radiating portion A1, and the second radiating portion A2cooperatively form a first antenna to excite the LTE-A low, mid, andhigh-frequency modes. The second feed source 14 b and the thirdradiating portion A3 cooperatively form a second antenna to excite asecond group of LTE-A mid and high-frequency modes.

FIG. 22 shows a graph of scattering values (S11 values) of the LTE-Alow-frequency mode. A plotline S221 represents S11 values of the firstantenna. A plotline S222 represents S11 values of the second antenna.

FIG. 23 shows a graph of total radiation efficiency of the LTE-A mid andhigh-frequency modes. A plotline S231 represents LTE-A mid andhigh-frequency mode of the first antenna. A plotline S232 represents atotal radiation efficiency of the second antenna.

FIG. 24 shows a graph of total radiation efficiency of the LTE-Alow-frequency mode of the first antenna.

As shown in FIGS. 22-24, the low-frequency mode is excited by the firstantenna, and the switching circuit 17 adjusts the low-frequency mode toinclude the LTE-A Band17, the LTE-A Band13, the LTE-A Band20, and theLTE-A Band8. The first antenna and the second antenna of the antennastructure 100 b both are capable of activating the LTE-A mid andhigh-frequency modes (1710-2690 MHz).

The embodiments shown and described above are only examples. Even thoughnumerous characteristics and advantages of the present technology havebeen set forth in the foregoing description, together with details ofthe structure and function of the present disclosure, the disclosure isillustrative only, and changes may be made in the detail, including inmatters of shape, size and arrangement of the parts within theprinciples of the present disclosure up to, and including, the fullextent established by the broad general meaning of the terms used in theclaims.

What is claimed is:
 1. An antenna structure comprising: a housingcomprising a middle frame and a border frame, wherein the middle frameand the border frame are made of metal, the border frame is mountedaround a periphery of the middle frame, the border frame comprises aslot, a first gap, and a second gap, the slot is in an inner side of theborder frame, the first gap and the second gap are in the border frame,the slot, the first gap, and the second gap divide the border frame intoa first radiating portion, a second radiating portion, and a thirdradiating portion, the first radiating portion is insulated from themiddle frame by the slot; a first feed source electrically coupled tothe first radiating portion and adapted to provide an electric currentto the first radiating portion; a second feed source electricallycoupled to one of the second radiating portion or the third radiatingportion, another one of the second radiating portion or the thirdradiating portion being electrically coupled to the first radiatingportion; wherein: a thickness of the border frame is greater than orequal to twice a width of the first gap or twice a width of the secondgap; and a width of the slot is less than or equal to half the width ofthe first gap or half the width of the second gap.
 2. The antennastructure of claim 1, wherein: the border frame comprises an endportion, a first side portion, and a second side portion; the first sideportion and the second side portion are respectively coupled to oppositeends of the end portion; the first gap is in the end portion adjacentthe first side portion, and the second gap is in the end portionadjacent the second side portion; the slot is in an inner side of theend portion and extends toward the first side portion and the secondside portion; the first radiating portion is defined in a portion of theborder frame between the first gap and the second gap; a secondradiating portion is defined in a portion of the border frame betweenthe first gap and an endpoint of the first side portion. the thirdradiating portion is defined in a portion of the border frame betweenthe second gap and an endpoint of the second side portion.
 3. Theantenna structure of claim 2, wherein: a portion of the border framebetween the first feed source and the first gap defines a firstradiating section; a portion of the border frame between the first feedsource and the second gap defined a second radiating section; the secondfeed source is electrically coupled to the second radiating portion;when the first feed source supplies the electric current, the electriccurrent from the first feed source flows through the first radiatingsection to excite a first resonant mode and generate a radiating signalin a first frequency band; the electric current from the first feedsource flows through the second radiating section and is electricallycoupled to the third radiating portion through the second gap to excitea second resonant mode and generate a radiation signal in a secondfrequency band; when the second feed source supplies the electriccurrent, the electric current from the second feed source flows throughthe second radiating portion to excite a third resonant mode andgenerate a radiation signal in a third frequency band.
 4. The antennastructure of claim 3, wherein: the first resonant mode is a Long TermEvolution Advanced (LTE-A) low-frequency mode; the second resonant modeis an LTE-A mid-frequency mode; the third resonant mode is an LTE-Ahigh-frequency mode.
 5. The antenna structure of claim 3 furthercomprising two extending portions; wherein: one of the two extendingportions is electrically coupled to an end of the second radiatingsection adjacent to the second gap; and a second one of the twoextending portions is electrically coupled to an end of the thirdradiating portion adjacent to the second gap; and the two extendingportions face to each other.
 6. The antenna structure of claim 2,wherein: the second feed source is electrically coupled to the thirdradiating portion; when the first feed source supplies the electriccurrent, the electric current from the first feed source flows throughthe first radiating portion to excite a first resonant mode and generatea radiation signal in a first frequency band; the electric current fromthe first feed source flows through the first radiating portion and iselectrically coupled to the second radiating portion through the firstgap to excite a second resonant mode and generate a radiation signal ina second frequency band; the electric current from the first feed sourceflows through the third radiating portion to excite a third resonantmode and generate a radiation signal in a third frequency band.
 7. Theantenna structure of claim 6, wherein: the first resonant mode is anLTE-A low-frequency mode; the second resonant mode is an LTE-Amid-frequency mode; and the third resonant mode is an LTE-Ahigh-frequency mode.
 8. The antenna structure of claim 6 furthercomprising two extending portions; wherein: one of the two extendingportions is electrically coupled to an end of the first radiatingsection adjacent to the first gap; and a second one of the two extendingportions is electrically coupled to an end of the second radiatingportion adjacent to the first gap; and the two extending portions faceto each other.
 9. The antenna structure of claim 2, wherein: a portionof the border frame between the first feed source and the first gapdefines a first radiating section; a portion of the border frame betweenthe first feed source and the second gap defines a second radiatingsection; the second feed source is electrically coupled to the thirdradiating portion; when the first feed source supplies the electriccurrent, the electric current from the first feed source flows throughthe first radiating section toward the first gap to excite a firstresonant mode and generate a radiation signal in a first frequency band;the electric current from the first feed source flows through the secondradiating section toward the second gap to excite a second resonant modeand generate a radiation signal in a second frequency band; the electriccurrent from the first feed source flows through the first radiatingsection and is electrically coupled to the second radiating portionthrough the first gap to excite a third resonant mode and generate aradiation signal in a third frequency band; when the second feed sourcesupplies the electric current, the electric current from the second feedsource flows through the third radiating portion to excite a fourthresonant mode and generate a signal in a fourth frequency band.
 10. Theantenna structure of claim 9, wherein: the first resonant mode is anLTE-A low-frequency mode; the second resonant mode is an LTE-Amid-frequency mode; the third resonant mode is an LTE-A high-frequencymode; and the fourth resonant mode is an LTE-A mid-high-frequency mode.11. The antenna structure of claim 9, wherein: a first antenna comprisesthe first feed source, the first radiating portion, and the secondradiating portion, the first antenna being adapted to excite a resonantmode in an LTE-A low, middle, and high-frequency mode; a second antennacomprises the second feed source and the third radiating portion, thesecond antenna being adapted to excite a resonant mode in an LTE-Amid-high-frequency mode; and the first antenna and the second antennacooperative form a multi-input and multi-output antenna structure. 12.The antenna structure of claim 1, wherein the middle frame and theborder frame are integrally formed.
 13. The antenna structure of claim 3further comprising a switching circuit comprising a switching unit andat least one switching component, wherein: the switching unit iselectrically coupled to the first radiating section; the at least oneswitching component is electrically coupled in parallel; one end of eachof the at least one switching component is electrically coupled to theswitching unit, and another end of each of the at least one switchingcomponent is electrically coupled to ground; the switching unit switchesa connection between the first radiating section and the at least oneswitching component to adjust a frequency of the first frequency band.14. The antenna structure of claim 6 further comprising a switchingcircuit comprising a switching unit and at least one switchingcomponent, wherein: the switching unit is electrically coupled to thefirst radiating section; the at least one switching component iselectrically coupled in parallel; one end of each of the at least oneswitching component is electrically coupled to the switching unit, andanother end of each of the at least one switching component iselectrically coupled to ground; the switching unit switches a connectionbetween the first radiating section and the at least one switchingcomponent to adjust a frequency of the first frequency band.
 15. Theantenna structure of claim 9 further comprising a switching circuitcomprising a switching unit and at least one switching component,wherein: the switching unit is electrically coupled to the firstradiating section; the at least one switching component is electricallycoupled in parallel; one end of each of the at least one switchingcomponent is electrically coupled to the switching unit, and another endof each of the at least one switching component is electrically coupledto ground; the switching unit switches a connection between the firstradiating section and the at least one switching component to adjust afrequency of the first frequency band.
 16. A wireless communicationdevice comprising an antenna structure comprising: a housing comprisinga middle frame and a border frame, wherein the middle frame and theborder frame are made of metal, the border frame is mounted around aperiphery of the middle frame, the border frame comprises a slot, afirst gap, and a second gap, the slot is in an inner side of the borderframe, the first gap and the second gap are in the border frame, theslot, the first gap, and the second gap divide the border frame into afirst radiating portion, a second radiating portion, and a thirdradiating portion, the first radiating portion is insulated from themiddle frame by the slot; a first feed source electrically coupled tothe first radiating portion and adapted to provide an electric currentto the first radiating portion; a second feed source electricallycoupled to one of the second radiating portion or the third radiatingportion, another one of the second radiating portion or the thirdradiating portion being electrically coupled to the first radiatingportion; wherein: a thickness of the border frame is greater than orequal to twice a width of the first gap or twice a width of the secondgap; and a width of the slot is less than or equal to half the width ofthe first gap or half the width of the second gap.
 17. The wirelesscommunication device of claim 16, wherein: the border frame comprises anend portion, a first side portion, and a second side portion; the firstside portion and the second side portion are respectively coupled toopposite ends of the end portion; the first gap is in the end portionadjacent the first side portion, and the second gap is in the endportion adjacent the second side portion; the slot is in an inner sideof the end portion and extends toward the first side portion and thesecond side portion; the first radiating portion is defined in a portionof the border frame between the first gap and the second gap; a secondradiating portion is defined in a portion of the border frame betweenthe first gap and an endpoint of the first side portion. the thirdradiating portion is defined in a portion of the border frame betweenthe second gap and an endpoint of the second side portion.
 18. Thewireless communication device of claim 17, wherein: a portion of theborder frame between the first feed source and the first gap defines afirst radiating section; a portion of the border frame between the firstfeed source and the second gap defined a second radiating section; thesecond feed source is electrically coupled to the second radiatingportion; when the first feed source supplies the electric current, theelectric current from the first feed source flows through the firstradiating section to excite a first resonant mode and generate aradiating signal in a first frequency band; the electric current fromthe first feed source flows through the second radiating section and iselectrically coupled to the third radiating portion through the secondgap to excite a second resonant mode and generate a radiation signal ina second frequency band; when the second feed source supplies theelectric current, the electric current from the second feed source flowsthrough the second radiating portion to excite a third resonant mode andgenerate a radiation signal in a third frequency band.
 19. The wirelesscommunication device of claim 17, wherein: the second feed source iselectrically coupled to the third radiating portion; when the first feedsource supplies the electric current, the electric current from thefirst feed source flows through the first radiating portion to excite afirst resonant mode and generate a radiation signal in a first frequencyband; the electric current from the first feed source flows through thefirst radiating portion and is electrically coupled to the secondradiating portion through the first gap to excite a second resonant modeand generate a radiation signal in a second frequency band; the electriccurrent from the first feed source flows through the third radiatingportion to excite a third resonant mode and generate a radiation signalin a third frequency band.
 20. The wireless communication device ofclaim 17, wherein: a portion of the border frame between the first feedsource and the first gap defines a first radiating section; a portion ofthe border frame between the first feed source and the second gapdefines a second radiating section; the second feed source iselectrically coupled to the third radiating portion; when the first feedsource supplies the electric current, the electric current from thefirst feed source flows through the first radiating section toward thefirst gap to excite a first resonant mode and generate a radiationsignal in a first frequency band; the electric current from the firstfeed source flows through the second radiating section toward the secondgap to excite a second resonant mode and generate a radiation signal ina second frequency band; the electric current from the first feed sourceflows through the first radiating section and is electrically coupled tothe second radiating portion through the first gap to excite a thirdresonant mode and generate a radiation signal in a third frequency band;when the second feed source supplies the electric current, the electriccurrent from the second feed source flows through the third radiatingportion to excite a fourth resonant mode and generate a signal in afourth frequency band.